COLOR TYPES FOR GRANDIDIERITE
Grandidierite is a mineral that was first discovered in 1902 in southern Madagascar near Tolianaro (formerly Fort-Dauphin), and in Sri Lanka. With a chemical formula of (Mg, Fe2+)Al3(BO3)(SiO4)O2, the mineral belongs to the orthorhombic crystal system.
A rather rare mineral and known as one of the most expensive gemstones a milky green color with a surprising element of pleochroism, translucent to transparent blue-green is seldom seen in gem or jewelry collections.
Grandidierite display strong trichroic pleochroism. That means they can show three different colors depending on the viewing angle: dark greenish Blue, yellowish Green, colorless (sometimes light yellow or dark green).